But the "city farm" once proposed for a portion of the Ultimo site adjoining the Powerhouse Museum has been scaled back to a garden.

The commercial food and beverage component was pitched as another potential drawcard to the 500-metre linear park, a wi-fi-enabled civic ‘‘spine’’ running through the centre of a revitalised cultural and education precinct.

Sydney Harbour Foreshore Authority’s Darling Harbour director, Debra Dawson, said expressions of interest could open as soon as this year.

"The commercial elements will also contribute to the identity of the project," she said. "So we’re looking for things that are exceptionally complementary and sustainable and they may run and manage the event side."

The development application for the Goods Line is expected to be lodged with the City of Sydney in a matter of weeks, with work to begin in June if it is approved. The authority put the project’s budget at between $5 million and $10 million.

It's anticipated 2014 opening would coincide with that of the University of Technology’s nearby business school building, designed by the Canadian-American architect Frank Gehry.

Sydney’s lord mayor Clover Moore said the Goods Line would connect the area between Surry Hills and Darling Harbour for pedestrians.

‘‘It’s really knitting back the city as should have occurred when Darling Harbour first went ahead,’’ she said.

Cr Moore joined with the Planning Minister, Brad Hazzard, in drawing parallels between the project and New York’s High Line – a 2.3km park along an old freight line, nine metres above the city.

The Goods Line will stand four metres above the city at its highest point.

‘‘We really want this to be Sydney’s version, but better, of New York’s High Line,’’ Mr Hazzard said.

The Powerhouse Museum’s manager of strategy and planning, Peter Morton, said the High Line was a more passive space than that planned for the Ultimo site.

A cafe could be connected to a ‘‘transformer’’ building in the centre of the civic corridor, which the Powerhouse also intended to use to ‘‘come outside the walls of the museum’’, he said.

‘‘From the museum’s perspective, we’ll want to run public programs and a whole series of events and other things in that space,’’ he said.

But the room for the urban agriculture plot known as the ‘‘city farm’’ was ‘‘much smaller than initially envisaged’’ by an earlier feasibility study, he said.

The council had identified the disused Powerhouse Museum car park as one of two possible sites for the full-scale project, which is now earmarked for Sydney Park at St Peters.

A city spokeswoman said council and the museum had been consulting with the Sydney Harbour Foreshore Authority and Infrastructure NSW about the smaller plot.

"They support the project and have their designers looking at the best way for the City Farm to be integrated with The Goods Line and the new convention centre," she said.